The ancient art of investment or lost wax casting can be used to make a variety parts. These include turbocharger wheels and golf club heads as well as electronic boxes and hip replacement implant kits.
Although heavily dependent upon aerospace and defense outlets, the industry has grown to accommodate a wider range of applications.
The roots of investment casting are in the Second World War’s heavy requirements. However, it was only after the introduction of jet propulsion to military and civilian aircraft that the lost wax casting technique became one of the most important techniques in modern industry.
The 1980s saw investment casting expand rapidly worldwide, in order to fulfill growing needs for airframe and engine parts. Investment casting today is an important part of the foundry sector. It now accounts for 15% of all UK cast metal production.
It is the modernization or reinterpretation of an older art.
Since at least six centuries ago, lost wax casting has been used in jewellery and sculpture. The technique was first used for dental inlays (and later surgical implant) around 100 years ago. The demand for modern technology grew during World War II. Gas turbines were introduced to prod military aircrafts. This transformed the old craft into an advanced metal-forming process.
Designers increased the engine’s efficiency by increasing inlet gas temperatures, so turbine blades had to withstand high temperatures. The metal casting technique is a long-standing and valuable tool in modern technology. Lost wax casting was the basis for the invention of this process.
Lost Foam Casting is also known. Lost Foam Casting – What does it mean?
LFC, or lost foam casting (LFC), is a method of casting metals that makes use expendable foam patterns. The foam pattern remains in the mould when metal pouring is done with lost foam casting. This is where molten steel replaces the foam.
Producing the casting
H.F. Shroyer patented the use of foam patterns in metal casting during 1958. Shroyer’s patent shows that a pattern was created from expanded polystyrene blocks (EPS) and supported with bonded soil during pouring. This is called the “full mould” process.
Full moulding is a process that produces large-scale, unique castings. The pattern is typically machined using an EPS block. The lost foam method was the original term for full-moulding. Current patents require that full mold be used as the generic name for the process.
M.C. Fleming used dry unbonded silica sand in the process. Today, this is called lost foam casting (LFC). LFC is a moulding method that uses polystyrene beads to create the foam pattern. LFC can be distinguished from full-moulding by using unbonded sand (LFC), as opposed to the traditional mould method.
Full moulding process for bonded sand
There are many ways to refer to foam casting techniques. These include lost foam, foamcasting, foam vaporization casting and evaporative casting.
These terms can cause confusion for casting producers, design engineers and casting users. The lost foam process has even been adopted by people who practice the art of home hobby foundry work, it provides a relatively simple & inexpensive method of producing metal castings in the backyard foundry.
Col Croucher.